Known dispensing or distributing machines for fluid products, such as for example dyes of different shade or color, able to be dosed and/or added to a basic substance so as to form a paint of a determinate color, comprise a plurality of delivery nozzles, of variable number, from some units to some tens, which are grouped together in a delivery head. Each delivery nozzle is connected to a corresponding tank containing a determinate dye and is controlled by an electro-pump which cause the selective delivery of the fluid product in a quantity appropriately chosen, for example with the aid of an electronic processor.
Normally, in the use of such dispensing machines, it is necessary to deliver only a few fluid products at a time, with the consequence that the fluid products, which are not delivered frequently, remain stationary in correspondence with the inactive nozzles and tend to dry out, creating problems at the moment when they need to be delivered.
For example, a device is known, described in the Italian patent application for industrial invention UD2004A000094, filed on Nov. 5, 2004 in the name of the present Applicant. This known device is able to be associated with the delivery head, to keep the terminal parts of the delivery nozzles at a controlled temperature and level of humidity, so as to prevent the drying of the fluid products which are not delivered frequently, limiting the errors in measurement of the quantities delivered and the possible introduction of coagulated particles, which cannot be mixed, into the collection container of the finished product.
From the European patent application EP-A-1.510.260, published on Feb. 3, 2005, a method is also known, for conducting a humidification fluid to the nozzles by means of the micro-capillarity of a fabric (felt).
Producers of paints and varnishes increasingly feel the need to have a delivery head with a high number of nozzles, for example 24 or 32, divided into two or more groups, so as to deliver different types of dyes, such as for example universal dyes, industrial dyes with organic solvents, or decorative dyes, such as water dyes without VOCs (Volatile Organic Components).
In this case, known devices are not able to guarantee optimum humidification for the different groups of delivery nozzles, since the products delivered by each group have different characteristics and they must be humidified and preserved with different parameters and/or by means of different conditioning fluids, for example steam for water dyes and universal dyes and organic solvents for solvent dyes.
This disadvantage can also cause part of the products delivered to dry out, thus making some of the problems previously solved re-surface, such as the difficulty in measuring the delivery and the poor quality of the finished product.
One purpose of the present invention is to achieve a device, and to perfect a method, which prevent the drying of fluid products, also when the same delivery head is provided with different groups of nozzles, able to deliver fluid products with different characteristics.
Another purpose of the present invention is to achieve a device which is simple and economic to make and to use.
The Applicant has devised, tested and perfected the present invention, which brings a significant technical contribution to the state of the art, in order to obtain these and other purposes.